Removal and Inactivation of Nonenveloped and Enveloped Virus Surrogates by Conventional Coagulation and Electrocoagulation Using Aluminum and Iron

Abstract

The continued threat of contamination of municipal water supplies necessitates the systematic evaluation of the efficacy of existing unit processes to protect public health and develop new technologies to better attenuate a wide range of viruses in the water we drink. We compared four coagulation approaches (conventional alum and FeCl3 coagulation and aluminum and iron electrocoagulation) in terms of their ability to remove/inactivate an enveloped virus surrogate (ϕ6) and a nonenveloped virus surrogate (MS2) under identical experimental conditions. Facile removal and inactivation of ϕ6 by alum and FeCl3 indicated the ability of existing conventional treatment plants to well-attenuate enveloped viruses. MS2 was attenuated to a lower extent than ϕ6, indicating relatively weaker protection against nonenveloped viruses by conventional coagulation. Performance of aluminum electrocoagulation was akin to that of alum. In contrast, iron electrocoagulation significantly outperformed the other three approaches (given sufficient time) and was the sole technique capable of simultaneously inactivating and removing both bacteriophages. However, all four coagulation approaches ruptured the ϕ6 phospholipid envelope and damaged its nucleocapsid’s structural integrity. Only iron electrocoagulation resulted in the appearance of new presumptive carbonyl derivatives for MS2 and the trans geometric isomer of lipid hydrocarbon chains for ϕ6 in infrared spectra, indicating oxidative modifications to the MS2 protein capsid and the ϕ6 lipid envelope, respectively. Hence, this technology presents a harsh physicochemical environment capable of simultaneously removing and inactivating viruses.